<style lang="less">
  @import '../main.less';
</style>

<template>
  <div ref="scrollCon" @DOMMouseScroll="handlescroll" @mousewheel="handlescroll" class="tags-outer-scroll-con">
    <div class="close-all-tag-con">
      <Dropdown transfer @on-click="handleTagsOption">
        <Button size="small" type="primary">
          标签选项
          <Icon type="ios-arrow-down"></Icon>
        </Button>
        <DropdownMenu slot="list">
          <DropdownItem name="clearAll">关闭所有</DropdownItem>
          <DropdownItem name="clearOthers">关闭其他</DropdownItem>
        </DropdownMenu>
      </Dropdown>
    </div>
    <div ref="scrollBody" class="tags-inner-scroll-body" :style="{left: tagBodyLeft + 'px'}">
      <transition-group name="taglist-moving-animation">
        <Tag
          type="dot"
          v-for="(item, index) in pageTagsList"
          ref="tagsPageOpened"
          :key="item.name"
          :name="item.name"
          @on-close="closePage"
          @click.native="linkTo(item)"
          :closable="item.name==='home_index'?false:true"
          :color="item.children?(item.children[0].name===currentPageName?'primary':'default'):(item.name===currentPageName?'primary':'default')"
        >{{ itemTitle(item) }}</Tag>
      </transition-group>
    </div>
  </div>
</template>

<script>
  import Vue from 'vue';
  import VueI18n from 'vue-i18n';
  Vue.use(VueI18n);
  export default {
    name: 'tagsPageOpened',
    data () {
      return {
        currentPageName: this.$route.name,
        tagBodyLeft: 0,
        refsTag: [],
        tagsCount: 1
      };
    },
    props: {
      pageTagsList: Array,
      beforePush: {
        type: Function,
        default: (item) => {
          return true;
        }
      }
    },
    computed: {
      title () {
        return this.$store.state.app.currentTitle;
      },
      tagsList () {
        return this.$store.state.app.pageOpenedList;
      }
    },
    methods: {
      itemTitle (item) {
        if (typeof item.title === 'object') {
          return this.$t(item.title.i18n);
        } else {
          return item.title;
        }
      },
      closePage (event, name) {
        let pageOpenedList = this.$store.state.app.pageOpenedList;
        let lastPageObj = pageOpenedList[0];
        if (this.currentPageName === name) {
          let len = pageOpenedList.length;
          for (let i = 1; i < len; i++) {
            if (pageOpenedList[i].name === name) {
              if (i < (len - 1)) {
                lastPageObj = pageOpenedList[i + 1];
              } else {
                lastPageObj = pageOpenedList[i - 1];
              }
              break;
            }
          }
        } else {
          let tagWidth = event.target.parentNode.offsetWidth;
          this.tagBodyLeft = Math.min(this.tagBodyLeft + tagWidth, 0);
        }
        this.$store.commit('removeTag', name);
        this.$store.commit('closePage', name);
        pageOpenedList = this.$store.state.app.pageOpenedList;
        localStorage.pageOpenedList = JSON.stringify(pageOpenedList);
        if (this.currentPageName === name) {
          this.linkTo(lastPageObj);
        }
      },
      linkTo (item) {
        let routerObj = {};
        routerObj.name = item.name;
        if (item.argu) {
          routerObj.params = item.argu;
        }
        if (item.query) {
          routerObj.query = item.query;
        }
        if (this.beforePush(item)) {
          this.$router.push(routerObj);
        }
      },
      handlescroll (e) {
        var type = e.type;
        let delta = 0;
        if (type === 'DOMMouseScroll' || type === 'mousewheel') {
          delta = (e.wheelDelta) ? e.wheelDelta : -(e.detail || 0) * 40;
        }
        let left = 0;
        if (delta > 0) {
          left = Math.min(0, this.tagBodyLeft + delta);
        } else {
          if (this.$refs.scrollCon.offsetWidth - 100 < this.$refs.scrollBody.offsetWidth) {
            if (this.tagBodyLeft < -(this.$refs.scrollBody.offsetWidth - this.$refs.scrollCon.offsetWidth + 100)) {
              left = this.tagBodyLeft;
            } else {
              left = Math.max(this.tagBodyLeft + delta, this.$refs.scrollCon.offsetWidth - this.$refs.scrollBody.offsetWidth - 100);
            }
          } else {
            this.tagBodyLeft = 0;
          }
        }
        this.tagBodyLeft = left;
      },
      handleTagsOption (type) {
        if (type === 'clearAll') {
          this.$store.commit('clearAllTags');
          this.$router.push({
            name: 'home_index'
          });
        } else {
          this.$store.commit('clearOtherTags', this);
        }
        this.tagBodyLeft = 0;
      },
      moveToView (tag) {
        if (tag.offsetLeft < -this.tagBodyLeft) {
          // 标签在可视区域左侧
          this.tagBodyLeft = -tag.offsetLeft + 10;
        } else if (tag.offsetLeft + 10 > -this.tagBodyLeft && tag.offsetLeft + tag.offsetWidth < -this.tagBodyLeft + this.$refs.scrollCon.offsetWidth - 100) {
          // 标签在可视区域
          this.tagBodyLeft = Math.min(0, this.$refs.scrollCon.offsetWidth - 100 - tag.offsetWidth - tag.offsetLeft - 20);
        } else {
          // 标签在可视区域右侧
          this.tagBodyLeft = -(tag.offsetLeft - (this.$refs.scrollCon.offsetWidth - 100 - tag.offsetWidth) + 20);
        }
      }
    },
    mounted () {
      this.refsTag = this.$refs.tagsPageOpened;
      setTimeout(() => {
        this.refsTag.forEach((item, index) => {
          if (this.$route.name === item.name) {
            let tag = this.refsTag[index].$el;
            this.moveToView(tag);
          }
        });
      }, 1); // 这里不设定时器就会有偏移bug
      this.tagsCount = this.tagsList.length;
    },
    watch: {
      '$route' (to) {
        this.currentPageName = to.name;
        this.$nextTick(() => {
          this.refsTag.forEach((item, index) => {
            if (to.name === item.name) {
              let tag = this.refsTag[index].$el;
              this.moveToView(tag);
            }
          });
        });
        this.tagsCount = this.tagsList.length;
      }
    }
  };
</script>
